XmlReader 读取器读取内存流 MemoryStream 的注意事项

MemoryStream对象提供了无需进行IO就可以创建Stream的方法，XmlTextWriter和XmlReader提供快速书写和读取XML内容的方法，结合MemoryStream，就可以直接在内存中构造XmlTextWriter，并用XmlReader进行读取。

使用MemoryStream和XmlTextWriter进行书写XML,需要注意两点：XmlTextWriter.Flush操作和重设MemoryStream.Position = 0。

< html  xmlns ="http://www.w3.org/1999/xhtml" >
< head  runat ="server" >
   < title > XmlReader 读取器读取内存流 MemoryStream 的注意事项 </ title >
</ head >
< body >
   < form  id ="form1"  runat ="server" >
     < asp:Button  ID ="Button1"  runat ="server"  OnClick ="Button1_Click"  Text ="读取数据"   />
   </ form >
</ body >
</ html >

 

protected   void  Button1_Click( object  sender, EventArgs e)
     {
        Response.Clear();
        Response.ContentType = "text/xml";
        MemoryStream msXml = new MemoryStream();
        XmlTextWriter xmlWriter = new XmlTextWriter(msXml, Encoding.UTF8);
        xmlWriter.WriteStartElement("rss");
        xmlWriter.WriteAttributeString("version", "2.0");
        xmlWriter.WriteStartElement("channel");
        xmlWriter.WriteElementString("title", "【孟宪会之精彩世界】");
        xmlWriter.WriteElementString("link", "http://dotnet.aspx.cc/Rss.aspx");
        xmlWriter.WriteElementString("description", "NET开发技术。");
        xmlWriter.WriteElementString("language", "zh-CN");
        xmlWriter.WriteElementString("copyright", "Copyright 1999-2007【孟宪会之精彩世界】");
        xmlWriter.WriteElementString("managingEditor", "amxh[AT]21cn.com");
        xmlWriter.WriteStartElement("image");
        xmlWriter.WriteElementString("title", "【孟宪会之精彩世界】");
        xmlWriter.WriteElementString("width", "144");
        xmlWriter.WriteElementString("height", "35");
        xmlWriter.WriteElementString("link", "http://dotnet.aspx.cc/");
        xmlWriter.WriteElementString("url", "http://dotnet.aspx.cc/Images/LogoRss.gif");
        xmlWriter.WriteEndElement();

        //循环读出数据库内容列表，忽略
        //while (objReader.Read())
        //{
        //  xmlWriter.WriteStartElement("item");
        //  xmlWriter.WriteElementString("title", objReader.GetString(0));
        //  xmlWriter.WriteElementString("description", objReader.GetString(1));
        //  xmlWriter.WriteElementString("link", "http://dotnet.aspx.cc/article/a933b187-06c3-4263-9eec-414a54d9c815/read.aspx");
        //  xmlWriter.WriteElementString("pubDate", objReader.GetDateTime(3).ToString("G"));
        //  xmlWriter.WriteEndElement();
        //}
        //objReader.Close();
        xmlWriter.WriteStartElement("item");
        xmlWriter.WriteElementString("title", "ASP.NET 2.0中直接将Access数据库导入到Excel文件中");
        xmlWriter.WriteElementString("description", "ASP.NET 2.0中直接将Access数据库导入到Excel文件中");
        xmlWriter.WriteElementString("link", "http://dotnet.aspx.cc/article/a933b187-06c3-4263-9eec-414a54d9c815/read.aspx");
        xmlWriter.WriteElementString("pubDate", "Sat, 02 Dec 2006 09:39:58 GMT");
        xmlWriter.WriteEndElement();
        xmlWriter.WriteEndElement();
        xmlWriter.WriteEndElement();
        xmlWriter.Flush();  // 确保书写器更新到Stream中；
        msXml.Position = 0; // 重置流的位置，以便我们可以从头读取     
        XmlReader xmlReader = XmlReader.Create(msXml);
        while (xmlReader.Read())
        {
            if (xmlReader.Name == "rss")
            {
                Response.Write(xmlReader.ReadOuterXml());
            }
        }
        Response.End();
        msXml.Close();
        xmlWriter.Close();
        xmlReader.Close();
    }